Early programming of adult longevity: demographic and experimental studies

Early-life nutritional programming of longevity

Available data from both experimental and epidemiological studies suggest that inadequate diet in early life can permanently change the structure and function of specific organs or homoeostatic pathways, thereby ‘programming’ the individual’s health status and longevity. Sufficient evidence has accumulated showing significant impact of epigenetic regulation mechanisms in nutritional programming phenomenon. The essential role of early-life diet in the development of aging-related chronic diseases is well established and described in many scientific publications. However, the programming effects on lifespan have not been extensively reviewed systematically. The aim of the review is to provide a summary of research findings and theoretical explanations that indicate that longevity can be influenced by early nutrition.

Month of birth and mortality in Sweden: a nation-wide population-based cohort study

Background

Month of birth – an indicator for a variety of prenatal and early postnatal exposures – has been associated with life expectancy in adulthood. On the northern hemisphere, people born in the autumn live longer than those born during the spring. Only one study has followed a population longitudinally and no study has investigated the relation between month of birth and mortality risk below 50 years.

Methods and results

In this nation-wide Swedish study, we included 6,194,745 subjects, using data from population-based health and administrative registries. The relation between month of birth (January – December) and mortality risk was assessed by fitting Cox proportional hazard regression models using attained age as the underlying time scale. Analyses were made for ages >30, >30 to 50, >50 to 80 and >80 years. Month of birth was a significant predictor of mortality in the age-spans >30, >50 to 80, and >80 years. In models adjusted for gender and education for ages >30 and >50 to 80 years, the lowest mortality was seen for people born in November and the highest mortality in those born in the spring/summer, peaking in May for mortality >30 years (25‰ excess hazard ratio compared to November, [95% confidence interval = 16–34 ]) and in April for mortality >50 to 80 years (42‰ excess hazard ratio compared to November, [95% confidence interval = 30–55]). In the ages >80 years the pattern was similar but the differences in mortality between birth months were smaller. For mortality within the age-span >30 to 50 years, results were inconclusive.

Conclusion

Month of birth is associated to risk of mortality in ages above 50 years in Sweden. Further studies should aim at clarifying the mechanisms behind this association.

Season of birth and exceptional longevity: comparative study of american centenarians, their siblings, and spouses

This study explores the effects of month of birth (a proxy for early-life environmental influences) on the chances of survival to age 100. Months of birth for 1,574 validated centenarians born in the United States in 1880-1895 were compared to the same information obtained for centenarians' 10,885 shorter-lived siblings and 1,083 spouses. Comparison was conducted using a within-family analysis by the method of conditional logistic regression, which allows researchers to control for unobserved shared childhood or adulthood environment and common genetic background. It was found that months of birth have significant long-lasting effect on survival to age 100: siblings born in September-November have higher odds to become centenarians compared to siblings born in March. A similar month-of-birth pattern was found for centenarian spouses. These results support the idea of early-life programming of human aging and longevity.

Biogerontology in Ukraine: update

Recent biogerontological findings in Ukraine are critically reviewed. It is stressed that cooperation of efforts within and between departments, institutions and countries is an efficient mode of coping with the complex problems of aging. A wide spectrum of aging research was traditionally performed in state-funded institutions throughout the country, focusing primarily on the neuro-humoral regulation, immune system, adaptation, oxidative stress, comparative analysis and life span extension. Mitochondria and associated oxidative stress seem to be a crossroad of "wet" and in silico research traffics aimed underpinning mechanisms of aging and life span extension. For instance, the highest coefficients of determination of the mammalian maximum life span were associated with mitochondrial DNA base composition and insertions into the nuclear DNA (NUMTs). The main conclusions of the multidirectional investigative endeavors could concisely be described as: modifications of the mitochondrial membrane resulted in alterations in ROS generation, metabolism, and life span; coordinated action of the key antioxidant genes and enzymes is an important issue in successful aging; lateral hypothalamic area could be a morpho-functional center of anti-aging in CNS; lymphoid tissue microenvironment is crucial in determination of functionality of the transplanted cells; gene and polypeptide therapy proved to be a perspective approach in treatment of accelerated aging; artificial atmosphere with optimal gaseous composition could be an efficient mean for life span extension and viability enhancement.

Does ageing originate in utero?

Ageing still remains a conundrum on the cellular and molecular level, while environmental factors and interactions further increase the complexity of the ageing process. On the other hand is cancer, for which 20 years ago, it was proposed by Trichopoulos that it might have intrauterine origin. We herein discuss the idea that parameters such as the influence of insulin-like growth factor (IGF) signalling, of hormones and of the number of stem cells, as well as the effect of foetal and early life nutrition on ageing may also commence in utero and we provide epidemiological and biological data to advocate for this hypothesis. Finally, we analyse the public health implication of this hypothesis based on the World Health Organization (WHO) report that the burden of diseases, including ageing, may be due to impaired foetal development.

Life span alteration after irradiation in Drosophila melanogaster strains with mutations of Hsf and Hsps

The life span alteration after gamma-irradiation and/or paraquat treatment in Drosophila in wild type strain Canton-S and strains with mutations of heat shock factor (1-4 alleles) and heat shock proteins (Hsp70Ba ( 304 ), Hsp83 ( e6A ), Hsp22 ( EY09909 ), Hsp67Bb ( EY099099 )) was investigated. Chronic low-dose rate gamma-irradiation (0.017 and 0.17 cGy/h) on pre-imago stages was used as a priming dose (absorbed doses were 4 and 40 cGy). Paraquat, a free radical inducing agent, was a challenging factor (20 mM for 1 day). It was shown that chronic irradiation led to adaptive response in both sexes except homozygous males and females with mutations of Hsf ( 4 ) and Hsp70Ba ( 304 ). The gender-specific differences in stress response were discovered in wild type strain Canton-S, Hsp22 ( EY09909 ) Hsp67Bb ( EY09909 ) homozygotes and Hsp83 ( e6A ) heterozygotes: the adaptive response persisted in males, but not in females. Thus, Drosophila Hsp and Hsf mutation homozygotes did not demonstrate the adaptive response in the majority of cases, implying an important role of those genes in radiation hormesis and adaptation to stresses.

Cross-life stage and cross-generational effects of ? irradiations at the egg stage on Drosophila melanogaster life histories

The long-term effects of X-irradiation with 0.25, 0.5, 0.75 and 1 Gy of 1 h eggs on the fitness-related life history traits in adult Drosophila melanogaster fruit flies and their offspring were investigated. Following irradiation with 0.25, 0.5 and 0.75 Gy, both F0 and F1 flies have decreased adult body weight and increased locomotor (photo- and geotactic) activity, whereas metabolic rate measured as the rate of CO2 production was unchanged or even increased, and female fecundity was slightly reduced compared to appropriate controls. In some cases, irradiation resulted in hormetic effects increased resistance to both starvation and heat shock stresses as well as life extension. An explanation of the beneficial long lasting effects induced by early irradiation is offered, which suggests that these effects are due to cross-life stage and cross-generational adaptive phenotypic plasticity.